253 



DRAFT 



alter the outcome of such calculations. In reality, the number of Steller sea lions that 

 occur in Oregon throughout the year is probably greater than the estimate of 300 used 

 in Table 2.2.7-3, however, the actual number of sea lions present in any area at any 

 time are nearly impossible to estimate with much accuracy. Therefore, any 

 consumption estimates based on such numbers are also likely to be inaccurate. 



'The sex ratio of the northern sea lions in Oregon is assumed to be 1:1. ' 



No reference is provided to support this statement. A 1 : 1 sex ratio may be accurate for 

 newborn pups, but not necessarily for adults. This is an important consideration since 

 greater prey consumption rates for larger males are weighted evenly with those of 

 smaller females in the calculations wiUiin this report. In reality, large males probably 

 make up a relatively small portion of the total population when compared to females, 

 juveniles of both sexes, and pups combined. It is inappropriate to use average 

 estimated consumption rates for adult males and adult females, and apply them to the 

 total population (which includes hundreds of juveniles and pups) with equal weight. 



'The diet of all wintering sea lions off southern Vancouver 

 Island. . . (Olesiuk and Bigg, 1998). . . equals one percent of British 

 Columbia's total annual commercial landings of salmon. " 



The report briefly cites this conclusion of Olesiuk and Bigg (1988) and then appears to 

 ignore the implications of this conclusion. Assuming that British Columbia fisheries 

 are managed properly, the total commercial landings should not be expected to have a 

 significant negative impact on salmon populations. Therefore, the additional one 

 percent of the harvest amount taken by sea lions should have a minimal, if not 

 insignificant, affect on the commercial harvest, and an even smaller impact on total 

 salmonid populations in British Columbia. If this is the case in British Columbia, it is 

 difficult to believe that sea lions could play such a significant role in the reduction of 

 salmonid populations in Oregon (as this report suggests). 



"Seasonal aggregations of California sea lions near the mouth of the 

 Columbia River are believed to feed on large concentrations of smelt 

 (Eulachon sp.) (Beach et al. 1985). ' (emphasis added) 



The tepon implies that there is some doubt regarding the importance of pinniped 

 predation on smelt. Existing information supports that both seals and sea lions feed 

 heavily on smelt. The large smelt run during winter months is believed to attract seals 

 and sea lions into the Columbia River. Smelt is the most frequently consumed and 

 important prey of seals and sea lions in the Columbia River at that time of the year 

 (Beach et al. 1985; ODFW, WDW unpublished data). While some seals and sea lions 

 do remove salmon from gillnets, free-swimming salmon constitutes a minor dietary 

 component relative to Eulachon. 



A-47 



